Redux - Use the Spread Operator on Arrays

Tell us what’s happening:
I have the following code and I ‘think’ I am copying the array right way but is not letting me pass the test

Dispatching an action of type ADD_TO_DO on the Redux store should add a todo item and should NOT mutate state.

What am I missing?

Your code so far

const immutableReducer = (state = ['Do not mutate state!'], action) => {
  switch(action.type) {
    case 'ADD_TO_DO':
      // Don't mutate state here or the tests will fail
      let copiedState = [...state];
      return copiedState;
      return state;

const addToDo = (todo) => {
  return {
    type: 'ADD_TO_DO',

const store = Redux.createStore(immutableReducer);

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Challenge: Redux - Use the Spread Operator on Arrays

Link to the challenge:

You need to add the new todo item to the end of your copied state array.

do you mean like [...state, 'next item'] ?

sorry I got it now [...state, action.todo]

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